JP2009144275A - Hydrophilic polypropylene molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To impart excellent hydrophilicity to hydrophobic polypropylene fiber and to provide a product thereof inexpensively. <P>SOLUTION: The polypropylene molded product, e.g. a fiber and a nonwoven fabric contains a nonionic alkyl surfactant having a nonion part containing 3 mol or more of ethylene oxide and/or propylene oxide, in an amount of 0.2-1.0 wt.% on the surface of the molded product, and in an amount of 0.1-1.0 wt.% on the inside of the molded product, and a polyethylene much of which is finely dispersed in the vicinity of the surface of the molded product, in an amount of 0.5-10 wt.%. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hydrophilic polypropylene molded product such as a water absorbent nonwoven fabric such as a paper diaper, a battery separator, a water absorbent pad, and a wiper.

  In Non-Patent Document 1, Berggreiter et al. Blended PE and PEG block copolymers to modify the surface of HDPE, and the block copolymers bleed out when solidified, and the PEG portion, which is a hydrophilic group, was removed. It turned out to be coordinated on the HDPE surface.

  When producing filaments and staple fibers, a spinning oil is generally applied to the surface of 0.3 to 3% by weight with a roller or the like, so that polypropylene fibers that are hydrophobic fibers are also hydrophilized. However, since non-woven fabrics, injection-molded products, films, etc. generally do not have a process of imparting a hydrophilizing oil to the manufacturing process, they will be processed later after becoming a molded product, resulting in an increase in the number of processes. However, there is a drawback that it is expensive and tends to cause adhesion spots.

  Patent Document 1 discloses that an antifogging agent (surfactant) comprising a hydrophobic group such as a long-chain alcohol and a hydrophilic group such as PEG is generally used by being blended with an agricultural polyolefin film. Yes. The antifogging agent is added to the film in an amount of 0.5 to 1 W% based on the total film weight. However, the fiber surface area is 10 times or more of the film surface area. Similarly, in order to form such a surfactant layer on the fiber surface, it is necessary to add 5 to 10 W% of the surfactant. On the other hand, for example, in the case of ordinary polypropylene fiber, it is impossible to perform spinning by blending a large amount of surfactant of 5 W% due to yarn breakage or the like.

Patent Document 2 has a description as if it contained 3 W% surfactant as an example of polypropylene spinning, but when read carefully, Exxon Polybond 3155 (Compatibilizer block copolymer) was used as a rubber matrix in advance as a surfactant. It is manufactured as an additive. Therefore, it is not possible to mix and spin such a large amount of surfactant in polypropylene without using such an expensive rubbery compatibilizer block copolymer. In addition, since such a compatibilizer block copolymer can contain a large amount of a surfactant, the amount of the surfactant that bleeds on the surface of the polypropylene fiber is reduced, and as a result, a larger amount of the surfactant is blended. This is economically disadvantageous due to an increase in raw material costs due to the compatibilizer block copolymer formulation.
Macromolecules 25 (1992), 636-643 USP 5,262,233 JP-T-2004-523666

  The problem to be solved by the present invention is to impart excellent hydrophilicity to a molded product such as hydrophobic polypropylene fiber and to supply it at low cost.

  The polypropylene molded product of the present invention, for example, fibers and nonwoven fabrics, has 0.2 to 1.0 W% of a nonionic alkyl surfactant having a nonionic part of surfactant of 3 mol or more of ethylene oxide and / or propylene oxide on the surface of the molded product. This is a polypropylene molded product containing 0.1 to 1.0 W% in the molded product and 0.5 to 10 W% of polyethylene finely dispersed in the vicinity of the molded product surface.

  The polypropylene molded product of the present invention can be processed into a fiber, spunbond or meltblown nonwoven fabric by a general method, and is inexpensive and suitable for paper diapers, battery separators, water absorbent pads, wipers and the like. Moreover, since a hydrophilic surface is formed, the antistatic property and wiping property of the molded product of the present invention are improved.

The polypropylene molded product of the present invention has a nonionic alkyl surfactant in which the nonionic part of the surfactant is ethylene oxide or / and propylene oxide, 0.2 to 1.0 W% on the surface of the molded product, and 0.1 to 0.1 in the molded product. A polypropylene molded product containing 0.5 to 10 W% of polyethylene containing 1.0 W% and finely dispersed in the vicinity of the molded product surface.
In one form, the molded product is a fiber or a nonwoven fabric. Preferably, the alkyl moiety of the surfactant is a linear saturated hydrocarbon having 10 or more carbon atoms. Also preferred is a molded polypropylene product in which the surfactant ethylene oxide and / or propylene oxide is a trimer or more.

  The nonionic part of the nonionic alkyl surfactant is ethylene oxide or / and propylene oxide polymer. It is preferable that ethylene oxide and / or propylene oxide is a trimer or more because excellent hydrophilicity can be obtained at a lower blending amount.

  The alkyl part of the nonionic alkyl surfactant is a straight-chain saturated hydrocarbon having 10 or more carbon atoms, which is highly similar to PE, and is more preferable than a branched saturated hydrocarbon or a straight-chain unsaturated hydrocarbon. Preferably, the number of carbon atoms is 12 or more, more preferably 14 or more, which is economical because the required amount of the surfactant is reduced. In addition, it is preferable that the raw material for the alkyl part is alcohol, since the raw material for the alkyl part is more carboxylic acid than water to improve water permeability.

  Examples of the long chain alkyl alcohol include lauryl alcohol, myristyl alcohol, cetyl alcohol, and stearyl alcohol. These are not limited to natural products and may be synthetic products.

  In the present invention, a masterbatch containing, for example, 20 W% of the nonionic alkyl surfactant is produced without using a compatibilizer block copolymer. That is, in the present invention, a masterbatch with a high blending amount is produced by polyblending polypropylene and polyethylene and retaining a nonionic alkyl surfactant at the phase-separated interface. The reason why a large amount of surfactant which is conventionally considered impossible can be contained in the present invention is considered to be that the nonionic alkyl surfactant forms micelles at the phase-separated interface. Therefore, with the formation of stable micelles, the larger the area of the phase-separated interface, the higher the blended masterbatch can be obtained. In order to increase the phase-separated interfacial area, it is important to disperse more finely, and it is preferable to increase the shearing force during kneading. When a liquid side injection biaxial kneading extruder is used, the rotational speed is 1, 000 revolutions / minute or more is preferable. More preferably, it is 1,500 revolutions / minute or more.

  The amount of the surfactant on the surface of the polypropylene fiber of the present invention is 0.2 W% or more. When the fiber diameter is reduced, it is preferably 0.3 W% or more. In addition to the fiber surface, the surfactant is also present inside the fiber. The ratio of the surfactant on the fiber surface and inside the fiber varies depending on the amount of other additives. Generally, a heat-resistant agent and a light-proofing agent are blended in polypropylene, and the total amount of additives is 0.5 to 1 W%. When the amount of other additives is small, the amount of the surfactant remaining inside becomes large. Therefore, the compounding amount of the master batch is influenced by the fiber diameter, the total amount of additives contained in the raw material polypropylene, and the type of additive. In general, the masterbatch content should be 5W% for meltblown and 3W% for spunbond, and fine adjustment is appropriate.

  The production method of the polypropylene spunbond and meltblown nonwoven fabric of the present invention may be a production method and production equipment using a general masterbatch. For example, spunbond can be spun at a die temperature of 250 ° C and a meltblown die temperature of 280 ° C. Polypropylene multifilaments, filaments, tape yarns, and staples can also be produced without using spinning oil. It is also possible to produce the polypropylene fiber of the present invention by changing the biaxial extruder to a single-screw extruder for spinning which is generally used in the composition of the final product during spinning and spinning. However, since the equipment replacement cost is expensive, it is more economical to use the master batch and the conventional equipment.

Similarly, the production method of the polypropylene film of the present invention may be a production method and production equipment such as T-die method and inflation method using a general master batch, and can be produced at a die temperature of 250 ° C. In this case, since the nonionic alkyl surfactant can be effectively distributed on the surface, the amount of the nonionic alkyl surfactant can be greatly reduced as compared with the conventional method, which is more economical.
Similarly, the injection-molded product can be manufactured by using a master batch with a general manufacturing facility. Thus, the molded article of the present invention can be easily and inexpensively imparted with antistatic performance and antifouling performance to a resin molded product.

  Moreover, you may add and shape | mold an additive in the range which does not affect a product at the time of shaping | molding of the polypropylene molding of this invention. Additives include stabilizers such as light stabilizers, heat stabilizers and antioxidants, functional additives such as color pigments, fragrances, antibacterial agents and fungicides, and powders such as carbon, calcium carbonate, barium sulfate and silica , Reinforcing agents such as aramid fiber, synthetic fiber, natural fiber, recycled fiber, and paper pulp, and extender.

As a method for evaluating hydrophilicity, the fiber product was measured for the permeation rate of the 9 g salt / liter water per second according to INDA IST 70.3 (98).
The surface adhering amount of the surfactant was obtained by immersing 1 g of a fiber product sample in 30 ml of n-Hexane in a 50 ml Bayer bottle, shaking the amplitude 4 mm, amplitude 100 times / minute, 1 minute, and then quantifying the surface washing solution by liquid chromatography. . The surfactant content in the interior was subjected to Soxhlet extraction, extraction was repeated up to the number of extractions with an error of less than 3%, the extraction conditions were set here, and the extract was quantified with a liquid chromatograph.

Further details will be described in Examples.

Example 1
As a matrix polymer, 44 parts by weight of LDPE of Novatec (trade name) MFR5 manufactured by Nippon Polyethylene Co., Ltd. and 36 parts by weight of PP of Prime Polypro (trade name) MFR5 manufactured by Prime Polymer Co., Ltd. are quantitatively supplied from the hopper of a high-speed rotating twin screw extruder. 20 parts by weight of lauryl alcohol / ethylene oxide 3 mol adduct was quantitatively side-injected from the middle of the extruder with a plunger pump, screw rotation speed 1,200 rpm, maximum temperature 200 ° C., die temperature 190 ° C. It was extruded in the shape of a cord, rapidly cooled and cut to produce hydrophilic masterbatch pellets. When the masterbatch was produced, there was no ejection of molten lauryl alcohol / ethylene oxide 5 mol adduct from the nozzle, and there was no problem in operability. In the master batch of the present invention, the lauryl alcohol / ethylene oxide 5-mol adduct had a good yield of 18.8 W%.

3 parts by weight of the masterbatch and 97 parts by weight of PP of Prime Polypro (trade name) MFR50 are quantitatively supplied to a spunbond production apparatus. Manufactured.
This non-woven fabric surface had a lauryl alcohol / ethylene oxide 5-mole adduct of 0.28 W%. Further, the content of lauryl alcohol / ethylene oxide 5 mol adduct remaining in the fiber was 0.22 W%. The saline permeation rate of this nonwoven fabric was less than 1 second, and it showed a water permeation rate suitable for a paper diaper surface material.
Further, by SEM observation of a fractured surface obtained by cooling the nonwoven single fiber after cooling with liquid nitrogen, it was observed that PE was more finely dispersed in the vicinity of the fiber surface.

Comparative Example 1
The same amount of the master batch produced in Example 1 as in Example 1 was changed to 1.5 parts by weight and 98.5 parts by weight of PP of Prime Polypro ™ MFR50, and the produced saline solution of the nonwoven fabric The permeation speed was 38 seconds, and the water permeation speed was insufficient as a paper diaper surface material. This non-woven fabric surface had a lauryl alcohol / ethylene oxide 5-mole adduct content of 0.13 W%.

Comparative Example 2
In the same manner as in Example 2, instead of the masterbatch produced in Example 1, 0.6 part by weight of lauryl alcohol / ethylene oxide 5 mol adduct was dried on 99.4 parts by weight of PP of Prime Polypro ™ MFR50. Blended to produce a nonwoven fabric. The saline permeation rate of this nonwoven fabric was 60 seconds or more, and the water permeation rate was insufficient as a paper diaper surface material. This non-woven fabric surface had a lauryl alcohol / ethylene oxide 5 mol adduct of 0.09 W%. Since the matrix does not contain polyethylene, it is considered that the lauryl alcohol / ethylene oxide 5-mole adduct was uniformly dispersed in the fiber and the fiber surface amount was reduced.

Example 2
In the same manner as in Example 1, a master batch using an octyl alcohol / ethylene oxide 5 mol adduct having 8 carbon atoms instead of lauryl alcohol / ethylene oxide 5 mol adduct was used. The non-woven fabric had a saline permeation rate of 3 seconds, and showed a sufficient water permeation rate as a paper diaper surface material. The non-woven fabric surface octyl alcohol / ethylene oxide 5 mol adduct was 0.22 W%. The surface amount decreased because octyl alcohol had a lower affinity for polyethylene compared to lauryl alcohol, so it was considered that the octyl alcohol was more uniformly dispersed in the matrix polypropylene as in Comparative Example 2, and therefore the permeation rate was considered to be slightly slower. It is done.

Claims (4)

The nonionic alkyl surfactant whose nonionic part of the surfactant is ethylene oxide or / and propylene oxide is contained at 0.2 to 1.0 W% on the surface of the molding, and 0.1 to 1.0 W% inside the molding. Polypropylene molding containing 0.5 to 10 W% of polyethylene finely dispersed in the vicinity of the molding surface. The polypropylene molded article according to claim 1, wherein the molded article is a fiber or a nonwoven fabric. The polypropylene molding according to claim 1 or 2, wherein the alkyl part of the surfactant is a linear saturated hydrocarbon having 10 or more carbon atoms. The polypropylene molded article according to claims 1 to 3, wherein the surfactant ethylene oxide and / or propylene oxide is a trimer or more.